GP350 Vidio sync sound?

[n3chu]

Hi all, have a GP350 UHF that when in high power mode has a sound on the carrier that sounds just like the sync sound from a tv set. When I lower the power it pretty much goes away? Changed the PL freq and that dosent change it. Never had one apart so dont know where to start. any ideas. thank you . Davie n 3 c h u at atlanticbb dot net

[Will]

Hi Davie,

Do you have the correct antenna on your GP350? High vswr from an incorrect antenna can cause the noise, RF feedback, you mention.
Other possible causes are bad contact from the main board to the antenna mounting in the case. Bad antenna switch/jack on the mainboard.
Loose or missing mainboard shield.

These can cause RF feedback.

[n3chu]

Hi Will, nice to hear from you. The antenna apears to be the 1/4 wave standerd looking antenna not the broad band antenna like on the HT1000 has.same as the HT600 1/4 wave. I havent had it apart so cant answer your questions about the inside. I just thought it was funny that by lowering the power the "sync" sound went away but what you say is very worth looking into. I will start by changing the antenna. When my bench is cleaned up I will try your other suggestions. Still enjoying my little extender box. also thanks for replying to my message. Davie